As attacks linked to the misogynist “incel” movement mounted in recent years, authorities around the world have begun to treat the ideology as a more serious terrorism threat. Since 2014, men who call themselves “involuntary celibates” and blame women for their own lack of sexual and social status have carried out mass killings in California, Florida, and Toronto. On Wednesday, a judge in Canada delivered a guilty verdict for the perpetrator of the 2018 Toronto van attack, which left 10 people dead and 16 injured – the deadliest incident linked to the incel movement. In her verdict, the judge found that the attacker’s resentment towards women was one among several motivating factors, but experts warn that such incidents are becoming more frequent, and that the ideology behind them is spreading internationally. 2020 saw a string of incel-related incidents, including a machete attack at a Toronto massage parlor, a shooting at an Arizona mall which injured three people, a man who...